Characteristics and outcome after out-of-hospital cardiac arrest with the emphasis on workplaces: an observational study from the Swedish Registry of Cardiopulmonary Resuscitation

Background: Characteristics and outcome in out-of-hospital cardiac arrest (OHCA) occurring at workplaces is sparsely studied. Aim: To describe (1) the characteristics and 30-day survival of OHCAs occurring at workplaces in comparison to OHCAs at other places and (2) factors associated with survival after OHCAs at workplaces. Methods: Data on OHCAs were obtained from the Swedish Registry of Cardiopulmonary Resuscitation from 1 January 2008 to 31 December 2018. Characteristics and factors associated with survival were analysed with emphasis on the location of OHCAs. Results: Among 47,685 OHCAs, 529 cases (1%) occurred at workplaces. Overall, in the fully adjusted model, all locations of OHCA, with the exception of crowded public places, displayed significantly lower probability of survival than workplaces. Exhibiting a shockable rhythm was the strongest predictor of survival among patients with OHCAs at workplaces; odds ratio (95% CI) 5.80 (2.92-12.31). Odds ratio for survival for women was 2.08 (95% CI 1.07-4.03), compared with men. At workplaces other than private offices, odds ratio for survival was 0.41 (95% CI 0.16-0.95) for cases who did not receive bystander CPR, as compared to those who did receive CPR. Among patients who were found in a shockable rhythm were 23% defibrillated before arrival of ambulance, which was more frequent than in any other location. Conclusion: Out-of-hospital cardiac arrest occurring at workplaces and crowded public places display the highest probability of survival, as compared with other places outside hospital. An initial shockable cardiac rhythm was the strongest predictor of survival for OHCA at workplaces.